Unlike many other cases where communicating >2 GB can be done with a datatype workaround, MPI_PACK/UNPACK seem particularly vulnerable to the 32-bit integer representation issue. I don't know whether or not this has been discussed before (and apologize if my message is redundant). Is there a proposal for MPI_(UN)PACK_COUNT yet? Thanks, Jeff ---------- Forwarded message ---------- From: Christoph Sprenger <[email protected]> Date: Wed, Oct 3, 2012 at 3:10 AM Subject: [mpich-discuss] MPI_Pack max buffer size To: [email protected] Hi, just wanted to double check if there is a way to Pack/Unpack bigger char buffers than numeric_limits<int>::max() without tokenizing the message into multiple chunks ? seems like one of my messages is hitting these bounds unfortunately. Cheers, Christoph _______________________________________________ mpich-discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss -- Jeff Hammond Argonne Leadership Computing Facility University of Chicago Computation Institute [email protected] / (630) 252-5381 http://www.linkedin.com/in/jeffhammond https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond